Two-blade reciprocating saw device



Dec. l2, 1950 K. w. CousE 2,534,001

TWO-BLADE RECIPROCATING SAW DEVICE Filed DBG. '7, 1945 2 Sheets-Sheet 1Dec. 12, 1950 K. w. coUsE TWO-BLADE RECIPROCATING SAW DEVICE 2Sheets-Sheet 2 Filed Dec. 7, 1945 Patented Dec. 12, 1950 UNITED STATESPATENT FFICE 2,534,001 TWO-BLADE RECIPROCATING SAW DEVICE Kibbey W.Couse, Newark, N. l. Application December 7, 1945, Serial No. 533,341.

6 Claims. 1

This invention relates particularly to power operated saws.

The ordinary motor operated hack saws are unsatisfactory especiallybecause they are dirticult to handle during sawing operations as the sawblade in moving in one direction hangs on the work thereby producing akicking action. Various attempts have been made to overcome thisdifliculty by providing two saw blades in side-by-side relation andsimultaneously recip rocating the blades in opposite directions. in allof such devices with which applicant is aware the blades are `providedwith guides or supports at both ends of the blades for positivelyguiding them. rThis reduces the flexibility o the blades and limits theusefulness oi the saw to certain kinds of work only. Furthermore, insome oi such devices, it is necessary to provide some sort of means onthe ends of the blades opposite the driving mechanism to maintain theblades under tension. With such saws, it is very dinicult if notimpossible to get around obstacles in the path of the work to beoperated upon in order to cut said work. In other saws, the blades areso mounted that they tend to wander laterally at the start of a saw cutor buckle during the cutting operation.

A primary object of my invention is to overcome the foregoing and otherobjections and difficulties. This I accomplish by providing a motoroperated saw having tufo saw blades in side-by-side relation with theteeth of the ree spective blades pitched in opposite directions and -bysimultaneously reciprocating` the blades in opposite directions. yThemotion of one blade in one direction offsets or compensates for themotion of the other blade in the other direction whereby all kicking orbuckling is eliminated or neutralized. The blades are so mounted andguided that their outer ends are free yet press against each other underall conditions of use thereby preventing any tendency oi the free endsto separate or buckle. Novel mechanism is provided ior reciprocating theblades whereby a continuous sawing action is had.

A further object of my invention is the provi' sion of a saw of thischaracter which is simple in construction, thoroughly reliable andclicient in operation, speedy and inexpensive to n1anufacture.

The invention will be better understood fromV the following descriptiontaken in connection with the accompanying drawings in which Figure l isa top plan view of a saw embodying one form of my invention.

Figure 2 is a sectional view taken on the plane of the line 2 2 ofFigure 1.

Figure 3 is a view similar to Figure 1 with the motor and top plateremoved.

Figure 4 is an enlarged fragmentary side View of the blades shown inFigure 1.

Figure 5 is a sectional view taken on the plane of the line 5 5 ofFigure 1.

Figure 6 is a sectional view taken on the plane of the line ii-li ofFigure 1.

Figure '7 is a bottom plan view of one of the blades.

Figure 8 is a bottom plan View. of a modiied form of blade adapted foruse with the improved saw.

Figure 9 is a fragmentary view oi the improved saw in position forcutting 01T a stud in an enclosed recess.

Figure i0 is a plan View of a modified form of improved saw.

Figure 11 is a sectional view taken on the plane of the line I l-ll ofFigure 10.

Figure l2 is a view similar to Figure the motor and top plate removed.

Figure 13 is a sectional View taken plane of the line |3l3 of Figure l0.

Figure 14 is a sectional View taken plane of the line ill- I4 of Figure10.

Figure 15 is a sectional view taken plane of the line I5-I5 of Figure10.

Figure 16 is a bottom plan View of one of the blades shown in Figure 10.

Figure 17 is a bottom plan view of a modiiied form of blade adapted tobe used with the improved saw shown in Figure 10.

Figure 18 is a fragmentary side view of still another modified form ofblade adapted to be used with the saw shown in Figure 10.

Referring to Figures 1 to 9, inclusive, the saw shown therein comprisesa casing having a base plate i and a removable cover plate 2. A handle 3is mounted on the rear'of the base plate and another handle t on thecover plate adjacent the front thereof. An electric motor 5 is :mountedon the cover plate adjacent its rear and to the rear oi the motor isanother handle 5. The motor shaft l extends downwardly through anopening 8 in the cover plate into a compartment Si in the casing. Aconductor l0 has one end connected to the motor and its other end (notshown) is adapted to be connected to a source of electromotive power. Adriving disc ll is connected to the inner end of the motor shaft and arocker arm l2 has one end connected by means of an eccentrically mountedpin i3 to said disc and its other end connected by means of aneccentrically mounted pin I4 to a disc I5 which is oscillatably mountedon a stud shaft I5 extending across the compartment 9 between the baseand cover plates.

A pair o1" cutting blades Il and I3 havingrows oi teeth It and Eil,respectively, are disposed in abutting relation through the majorportion of their lengths. The inner ends of the blades are connected bypins 2| to disc t5 at opposite points along its periphery as shown inFigure 3. The

li) with on the on the on the o blades are flexed, each toward theother, and pass from the disc i through a restricted passage 22 and:between and along spaced guide rollers 23 mounted in a compartment 215at the forward end of the casing and then outwardly through an opening25 to the exterior of the casing. By this arrangement, the blades arepressed together into abutting relationship and held substantially stiffand straight from a .point just inside the opening 25 to their outerends and tend to stay in sliding contact with each other inapproximately the plane that runs diametrically through the operatingdisc I5 perpendicularly to the pins 2|.

The teeth of each blade has what is known as a set, that is, the teethare arranged to project laterally at somewhat of an angle to the plane.of theY blade in order that the kerf made by the blade will be widerthan the thickness of said blade. Usually, the set is formed byalternately bending the teeth in opposite directions but in the presentinvention, principally owing to the fact that two blades are used, theteeth of each blade are bent only in one direction as shown in .Figures6 and 7. In this manner, when the blades are opposed to each other, theset of each blade extends outwardly and away from the other blade sothat they will not intersect the plane of the latter fblade. Thus thesets of the two blades combine to form what might be termed a double setwhich will be elective in cutting a kerf Vwithout undue friction uponthe blades or the material being cut. Also as shown in Figure 6, theteeth areV all tapered and each of certain teeth of each blade has itsinner face in abutting relation to the corresponding face of the opposedtooth of the other blade. Thus the two opposed teeth have their outer`faces in upwardly diverging relation and owing to this dispositionthereof, said teeth will cooperate, as the blades are reciprocatedthrough va kerf, to aid in maintaining said blades in close contact witheach other by reason of the pressure on outer surfaces. Between theabutting teeth, the other teeth of each blade are bent to divergeAoutwardly from the other blade. Furthermore, in order to secure thegreatest rapidity of cutting action, the teeth I9 and 2Q of therespective blades are pitched in opposite directions as clearly shown inFigure 4 so that as the blades are reciprocated, a cutting stroke willbe accomplished by either one or the other.

In Figure l, the saw is shown in position for cutting through a plate 26having an unobstructed and readily accessible Yupper surface. Figure 9shows the saw in a walled recess 2.7 with the blades ilexed and inposition for cutting a stud 28 projecting from the rear wall thereof,andnot accessible to the ordinary cutter.

Another type of blade `such as shown in Figure `8 Vmay also be used withthis form of the invention.v In this type, usually the toothed edge `29of the blade is corrugated so that portions thereof are 4oset atopposite sides of the longitudinal median line of the blade. For usewith this invention however the corrugations on one side of said medianline are ground 01T so that when two of such blades are opposed to eachother the corrugations of eachblade extend outwardly and away from theother blade so that they will not intersect vthe plane Vof the latterblade.

A In operation, when power is applied by the motor, which may becontrolled by a switch (not shown), the disc I I is rotated whichin turnthrough the rocker arm l2 oscillates the disc I 5 causing the blades toreciprocate alternately at great speed.

The handles 3, 4 and 6 are conveniently positioned so that the casingmay be readily grasped by .both hands and held in balanced position forcutting.

In the form of the invention shown in Figure l0, the base plate I isformed with an integral spacing bar 29 extending through the opening 25in the front of the casing to the exterior thereof. This bar serves tospace the blades 3B and 3I for practically Vtheir entire lengths. Theteeth 32 of each of the blades 30 and 3| has what is known as a set,that is, the teeth are arranged to project laterally at somewhat of anangle to the plane of the blade in order that the kerf made Yby theblade will be wider than the thickness of the blade. The set is formedby alternately bending the teeth in opposite directions as shown inFigure l5. In this manner, when the two blades are positioned abuttingagainst the spacing bar |29, certain of the teeth of each blade extendoutwardly and other teeth inwardly toward the other blade so that theyintersect the plane of the spacing zbar as shown in Figure l5.v Thespacing bar prevents the teeth of each blade from interfering with theteeth of the other blades and permits the use of blades having teeth setin the usual way.

The teeth of the respective blades 30 and 3I also are pitched inopposite directions the same the teeth of blades I1 and I8. This form ofthe invention is especially adapted for cutting a keyway 33 in acylindrical :bar 34 or the like extending from the end inwardly thereofas shown in Figure 10.

When it is desired to cut a keyway extending along the surface of acylindrical member such as the bar 35 of Figure 10, but remote from itsend, blades 35 and 36 of the form shown in Figure 18 are used with theimproved saw, instead of the blades 30 and 3|. Each of the blades 35 and36 is formed at its outer end with an arcuate cutting portion 31, withthe teeth 33 of each blade set so as to project laterally of the planeof the blade. The teeth of the respective blades are pitched in oppositedirections.

In Figure 1'?, another modied form of blade adapted for use with `thesaw of Figure l0 is illustrated. In this form, the toothed edge of theblade has corrugations 39 extending on opposite sides of thelongitudinal median line of the blade so that when such a blade ispositioned on each side of the spacing bar I29 the teeth of each bladewill be spaced from the teeth of the other blade.

In some cases it may be desirable to provide a top guide ange fill onthe` support or casing to be slidably engaged by the top or back edgesof the saw blades whereby the blades will be reinforced when it isdesired to press them forcibly into contact with the work.

Change in details may be made without departing from the principle andscope of the invention.

What I claim is: Y

1. The combination of two separate saw blades, and means for holdingsaid blades for simultaneous reciprocation in opposite directions withportions in close side-by-side relation, said means including a supporthaving a guideway in which said blades are slidably mounted and fromwhich said blades project at both ends, and an element on said supportbeyond one end of said guideway and interposed between and in contactwith said blades at one end thereof to ilex one end portion of one bladeaway .from the corresponding end portion of the other blade andsimultaneously force the other end portions of said blades toward eachother into close substantially stiff and parallel relation to eachother, whereby forces can be applied to said exed end portions of theblades to reciprocate the blades.

2. The combination as defined in claim 1 wherein the second-mentionedends of said blades are in sliding abutting contact with each other.

3. The combination as dened in claim 1 wherein said support has aspacing bar between the second-mentioned end portions and said bladesslidably abut opposite sides of said spacing bar.

4. The combination as dened in claim 1 wherein said support has aspacing bar between the second-mentioned end portions of said blades andthe teeth of said blades are pitched in opposite directions With theteeth of each blade extending laterally on both sides of the blade.

5. The combination set forth in claim 1 wherein said element isoscillatory and with the addition of means for oscillating said elementand operative connections between said element and the first-mentionedend portions of the blades for reciprocating them.

6. The combination as defined in claim 1 wherein said element comprisesan oscillatory disk disposed between and with its periphery in contactwith the first-mentioned end portions of said blades so that the diskholds the blades iiexed away from each other, operative connectionsbetween said blades and said disk for reciprocation of the blades uponoscillation of the disk, and means for oscillating the disk.

KIBBEY W. COUSE.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date Re. 14,210 Childs Oct. 31, 1916308,188 Miller Nov. 18, 1884 1,537,980 Asselin May 19, 1925 1,726,863Singer Sept. 3, 1929 1,789,804 Broillet Jan. 20, 1931 1,827,490 SpencerOct. 13, 1931 2,037,121 Dean Apr. 14, 1936 2,064,676 MacLeod Dec. 15,1936

